Conventionally, a trigger switch used in an electric tool is required to allow a large electric current to pass therethrough and to ensure a predetermined contact pressure at a contact so as to prevent chattering of the contact caused by vibration during an operation of the electric tool. For this end, there has been proposed a so-called seesaw type movable contact piece which directly rotates a switching bar (movable contact piece) 26 by a slide shaft 21 which reciprocates in an axial direction by an operation of an operation unit 11 (see patent literature 1). According to such a seesaw type movable contact piece, a sufficient contact pressure can be ensured at a contact 77 of the switching bar 26 due to the operation of the operation unit 11 and hence, chattering during the operation can be prevented whereby the seesaw type movable contact piece has high contact reliability.